Some users may have already seen a message from Instagram with a head's up that advertisements will soon be displayed in their streams.
It was about a year ago that Instagram started sprinkling ads into user streams in the U.S., and a similar move was made in the U.K. in September.
Instagram also recently launched video ads in the U.S.
Instagram, which was acquired by Facebook in April 2012 in a US$1 billion deal, says it has 200 million users worldwide.
The company says it has shared more than 20 billion photos to date and averages about 60 million daily.
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